The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed technology.
Ghosting is a phenomenon in which a replica of the received signal (audio and/or video) is super-imposed on the original signal. In case of an audio signal, such a replica may correspond to an echo of the original signal. In case of video signal, such a replica may be visible as one or more secondary boundaries around a significant boundary of one or more objects present in the original signal. In the analog domain, the ghosting phenomenon is common in scenarios in which the signal received by the receiver undergoes multiple reflections due to the obstacles present in the communication channel. It can also occur due to the reflections caused by impedance mismatch along the communication channel. Another form of ghosting manifests itself as edge misalignment of moving objects, or ‘shadowing’, within a given frame. Such frames may be captured in an interlaced video format one field at a time, and then subsequently weaved back together during display.
To detect and minimise the ghosting in the received signal, numerous methods have been developed. Such methods are based on transmission of a reference signal along with the original signal. In accordance with one of such techniques in the case of analog capturing of content, a Ghost Cancelling Reference (GCR) signal is transmitted along with the original signal during the Vertical Blanking Interval (VBI). A comparison is performed at the receiver between the original signal and the received signal based on the GCR signal, to minimise the ghosting. Other methods to detect and minimise ghosting that do not require reference signal have also been developed, for example, during High Dynamic Range (HDR) image generation that is typically used in the case of ghosting created during scene capture which has motion.
The ghost detection and minimisation based on inclusion of a reference signal along with the original signal is susceptible to errors. This is because along with the original signal, the reference signal may be transcoded and reformatted during transmission. As a result, any change in the reference signal may result in erroneous detection of the principal and/or secondary boundaries of one or more objects in the received signal. Further, the reference signal is an overhead as it is only used for a part of the decoding process.